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Ring Closure Reaction Pathway of a Diarylethene in Solution Using Femtosecond Time‐resolved Fluorescence Spectra
Author(s) -
Seo Kiho,
Eom Intae,
Shim Sangdeok,
Kim Chul Hoon,
Joo Taiha
Publication year - 2019
Publication title -
bulletin of the korean chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.237
H-Index - 59
ISSN - 1229-5949
DOI - 10.1002/bkcs.11689
Subject(s) - diarylethene , chemistry , thiophene , ring (chemistry) , photochromism , cyclopentene , fluorescence , photochemistry , spectral line , conformational isomerism , femtosecond , reaction rate constant , emission spectrum , time resolved spectroscopy , catalysis , kinetics , organic chemistry , molecule , laser , physics , quantum mechanics , astronomy , optics
Photochromic ring closure reaction dynamics of 1,2‐bis(2‐methylbenzo[ b ]thiophene‐3‐yl)hexafluoro cyclopentene is investigated by means of time‐resolved fluorescence spectra. Compared with a single wavelength probe, direct measurement of the emission spectra during the reaction provides unambiguous and straightforward picture for the ring closure reaction pathway. We observe two different emission bands in the fluorescence of the open ring isomer. From the global analysis for the spectra, we obtain <1 ps time constant for the ring closure reaction in polar solvent. Moreover, the ring closure reaction of the compound takes place entirely on the ultrafast timescale. The unreactive parallel conformer decays to the ground state by 150 ps time constant.